However, Herberman’s warning is based on early unpublished data, and many are remaining skeptical. Numerous reputable studies across the world – including a 2008 University of Utah study – have all concluded that there is no known link between cell phone use and brain tumors.

Herberman nevertheless defends his warning by taking a better-safe-than-sorry approach. “Really at the heart of my concern is that we shouldn’t wait for a definitive study to come out, but err on the side of being safe rather than sorry later,” he says. Herberman recommends that children should only use cell phones for emergencies because their brains are still developing while adults should keep the phone away from the head and use the speaker phone or a wireless headset.

Along with a previous University of Utah study indicating that driving while talking on the cell phone is equivelant to drunk driving, this study is another reason why more states should consider banning cell phones without ear pieces while driving.